Radar signal processing device, method and radar device and storage medium

Abstract

Provided are a radar signal processing device, method, and radar device that can more accurately detect a target based on a beat signal, and a storage medium. The radar signal processing device includes an extraction signal generation section that generates a processing signal based on a beat signal of a transmission signal and a reception signal, and generates a plurality of extraction beat signals by applying a plurality of window functions to the processing signal; a conversion section that converts the plurality of extraction beat signals into amplitude data representing a relationship between a distance and an amplitude; and a comprehensive data generation section that integrates a plurality of the amplitude data into comprehensive data.

Description

Technical Field

[0001] This invention relates to a radar signal processing device, a radar device, a radar signal processing method, and a storage medium for radar signal processing. Background Technology

[0002] Previously, techniques for removing interference waves from beat signals were known. For example, Patent Document 1 (US Patent No. 9,442,191) discloses a radar system as follows: In each of the parallel signal processing circuits—a first signal processing path and a second signal processing path—interference is removed from a copy of the beat signal. At least one window function is selected from a plurality of window functions with different frequency responses to be applied to the beat signal, converting the beat signal from a time region to a frequency region. Furthermore, the radar system combines the outputs of the first and second signal processing paths to generate an output beat signal. Here, in each of the first and second signal processing paths of the radar system, different interference removal methods and window functions are applied compared to the other parallel signal processing paths.

[0003] [Existing technical documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] US Patent No. 9,442,191 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] In the technology described in Patent Document 1, because the interference wave is removed from the beat signal, the range side lobe in the power spectrum generated based on the beat signal increases, sometimes making it impossible to accurately detect the target. A technology that surpasses the technology described in Patent Document 1 and can more accurately detect targets based on the beat signal is desired.

[0008] The present invention was made to solve the aforementioned problems, and its purpose is to provide a radar signal processing device, radar device, radar signal processing method, and radar signal processing program that can more accurately detect targets based on beat signals.

[0009] [Technical means to solve the problem]

[0010] This invention provides a radar signal processing apparatus. The radar signal processing apparatus includes: an extraction signal generation unit that generates a processed signal based on a beat signal between a transmitted signal and a received signal, and generates a plurality of extracted beat signals by applying a plurality of window functions to the processed signal; a conversion unit that converts the plurality of extracted beat signals into amplitude data representing the relationship between distance and amplitude; and a synthesis data generation unit that synthesizes the plurality of amplitude data into synthesis data.

[0011] In this way, multiple extracted beat signals are generated from the processed signal based on beat signals, each extracted based on different time ranges. These extracted beat signals are then converted into amplitude data, and composite data is generated by combining these amplitude data. This structure allows, for example, the generation of composite data using amplitude data from extracted beat signals that do not contain beat signals whose amplitudes are replaced to zero for interference removal. Therefore, it suppresses the increase in range sidelobes in the composite data caused by the replacement of a portion of the beat signal's amplitude to zero, enabling more accurate target detection based on composite data with smaller range sidelobes. Thus, more accurate target detection based on beat signals is possible.

[0012] Preferably, the integrated data generation unit selects the amplitude of one of the plurality of amplitude data into the integrated data corresponding to each of the distances.

[0013] Preferably, the first window function and the second window function among the plurality of window functions do not overlap in time.

[0014] Preferably, the third window function among the plurality of window functions overlaps with at least one of the first window function and the second window function.

[0015] Preferably, the plurality of window functions have the same type.

[0016] The present invention provides a radar device. Preferably, the radar device includes: the radar signal processing device described above; a transmitting unit configured to transmit the transmitted signal; and a receiving unit configured to receive a reflected signal reflected by a target.

[0017] Preferably, the transmitting unit transmits the signal via a rotating antenna.

[0018] Preferably, the receiving unit receives the reflected signal via a rotating antenna.

[0019] The present invention provides a radar signal processing method and a storage medium storing computer-executable instructions thereon, which, when executed by a computer, cause the computer to perform the following processing.

[0020] The radar signal processing method and the computer-executable instructions may include: generating a processed signal based on the beat signals of the transmitted and received signals; generating multiple extracted beat signals by applying multiple window functions to the processed signal; converting the multiple extracted beat signals into amplitude data representing the relationship between distance and amplitude; and combining the multiple amplitude data into composite data.

[0021] [The effects of the invention]

[0022] According to the present invention, targets can be detected more accurately based on beat signals. Attached Figure Description

[0023] Figure 1 This is a diagram showing the structure of a radar device according to an embodiment of the present invention.

[0024] Figure 2 This is a diagram showing the structure of the signal processing unit in a radar device according to an embodiment of the present invention.

[0025] Figure 3 This is a diagram illustrating the structure of the window function / Fast Fourier Transform (FFT) processing unit in the signal processing unit of an embodiment of the present invention.

[0026] Figure 4 This diagram illustrates an example of a beat signal received from the interference removal unit by the window function / FFT processing unit in the signal processing unit of an embodiment of the present invention.

[0027] Figure 5 This diagram illustrates an example of a beat signal received from the interference removal unit by the window function / FFT processing unit in the signal processing unit of an embodiment of the present invention.

[0028] Figure 6 This diagram illustrates an example of a window function used in the signal processing unit / FFT processing unit of an embodiment of the present invention.

[0029] Figure 7 This is a diagram illustrating an example of amplitude data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention.

[0030] Figure 8 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention.

[0031] Figure 9 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention.

[0032] Figure 10 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention.

[0033] Figure 11 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention.

[0034] Figure 12 This is a flowchart that specifies an example of the operation flow for generating comprehensive data by the radar device according to an embodiment of the present invention. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, identical or equivalent parts in the drawings will be labeled with the same symbols and their descriptions will not be repeated. Moreover, at least some of the embodiments described below may be combined arbitrarily.

[0036] [Structure and basic movements]

[0037] Radar Device

[0038] Figure 1 This is a diagram showing the structure of a radar device according to an embodiment of the present invention.

[0039] Reference Figure 1 The radar device 300 includes a radar unit 201 and a display processing unit 202. The radar unit 201 includes a signal generation unit 110, a transmission unit 120, a transmission antenna 130, a receiving antenna 140, a receiving unit 150, a mixer unit 160, an analog-to-digital (A / D) converter 170, and a signal processing unit 100. The signal processing unit 100 is an example of a radar signal processing device. For example, the radar device 300 is a frequency-modulated continuous wave (FM-CW) radar device mounted on a ship. The radar device 300 performs the following processing: displays the presence or absence of a target in the area monitored by the ship (i.e., the target area) and the echo image indicating the distance between the radar device 300 and the target on a display device (not shown).

[0040] The radar unit 201 outputs echo data to the display processing unit 202. This echo data represents the detection results of targets within the segmented target areas, which are divided into multiple regions. The transmitting antenna 130 and the receiving antenna 140 are rotated such that the azimuth angle of the transmitting antenna 130 relative to the radiation direction of the radio waves changes by a predetermined angle every predetermined sweep period T. The radar unit 201 outputs echo data from the multiple segmented target areas for each sweep period T to the display processing unit 202.

[0041] The display processing unit 202 performs the following processing: based on multiple echo data received from the radar unit 201, it displays an echo image of the detection target area on a display device.

[0042] Radar Department

[0043] The signal generation unit 110 repeatedly generates analog signals of a predetermined pattern and outputs them to the transmission unit 120. More specifically, during the sweep period T, the signal generation unit 110 outputs an analog signal generated by a modulation method such as FM-CW, whose frequency increases by a predetermined amount per unit time, to the transmission unit 120. Specifically, for example, the signal generation unit 110 includes a voltage generation unit and a voltage-controlled oscillator (VCO). During the sweep period T, the voltage generation unit generates an FM modulation voltage whose magnitude increases at a fixed ratio and outputs it to the VCO. The VCO generates an analog signal with a frequency corresponding to the magnitude of the FM modulation voltage received from the voltage generation unit and outputs it to the transmission unit 120.

[0044] The transmitting unit 120 transmits a transmission signal. More specifically, during the sweep period T, the transmitting unit 120 generates a radio frequency (RF) band transmission signal based on the analog signal received from the signal generation unit 110, and outputs the generated RF band transmission signal to the segmented target area via the transmitting antenna 130, which rotates along with the rotation of the radar unit 201. Furthermore, the transmitting unit 120 outputs the generated RF band transmission signal to the mixer unit 160. Specifically, for example, the transmitting unit 120 includes a mixer and a power amplifier. The mixer generates an RF band transmission signal based on the analog signal received from the signal generation unit 110, and outputs the generated transmission signal to the power amplifier and the mixer unit 160. In the transmitting unit 120, the power amplifier amplifies the transmission signal received from the mixer, and outputs the amplified transmission signal to the segmented target area via the transmitting antenna 130.

[0045] The receiving unit 150 receives the reflected signal, i.e., the signal reflected from the target, which is the transmitted signal. More specifically, the receiving unit 150 receives the reflected signal, i.e., the RF band signal, which is the signal reflected from the target area by the transmitted signal transmitted from the transmitting antenna 130, via the receiving antenna 140, which rotates along with the radar unit 201. Furthermore, the receiving unit 150 may also receive interference waves emitted by interfering objects via the receiving antenna 140. Interfering objects may be, for example, pulse radar devices located within or outside the target area. The receiving unit 150 outputs the signal received via the receiving antenna 140 to the mixer unit 160. Specifically, for example, the receiving unit 150 includes a low-noise amplifier. The low-noise amplifier amplifies the RF band received signal received via the receiving antenna 140 and outputs the amplified received signal to the mixer unit 160.

[0046] The mixer unit 160 generates a beat signal between the transmitted signal sent from the radar device 300 and the received signal received by the radar device 300. Here, the beat signal is a signal having a frequency component that differs between the frequency components of the transmitted signal sent from the transmitting unit 120 and the frequency components of the received signal received by the receiving unit 150. More specifically, the mixer unit 160 includes, for example, two mixers. A branch (not shown) branches the transmitted signal output from the transmitting unit 120 and assigns a 90° phase difference to the branched transmitted signal before outputting it to each mixer in the mixer unit 160. Similarly, a branch (not shown) branches the received signal output from the receiving unit 150 and outputs it to each mixer in the mixer unit 160. The two mixers in the mixer unit 160 perform multiplication operations on the transmitted and received signals respectively, thereby generating an analog beat signal SA comprising a group of I signals Si and Q signals Sq, which is then output to the A / D converter 170.

[0047] The A / D converter 170 converts the analog beat signal SA received from the mixer 160 into a digital signal SD, which consists of groups of I signals Si and Q signals Sq. More specifically, the A / D converter 170 samples at a predetermined sampling frequency during each sweep period T, thereby generating N beat signals SD, which consist of groups of N I signals Si and N Q signals Sq, and outputs them to the signal processing unit 100. N is an integer of 2 or more.

[0048] During each sweep period T, the signal processing unit 100 processes the N beat signals SD received from the A / D conversion unit 170 to generate echo data representing the detection results of the target in the segmented target area during each sweep period T. The signal processing unit 100 outputs the generated echo data to the display processing unit 202. Hereinafter, the beat signal SD with the sampling number n received by the signal processing unit 100 from the A / D conversion unit 170 during the sweep period T will also be referred to as the beat signal SD(n). n is an integer of 1 or more and N less, corresponding to the elapsed time counted from the start of the sweep period T. The beat signal SD(n) is a group of signals including the I signal Si(n) with the sampling number n and the Q signal Sq(n) with the sampling number n.

[0049] Alternatively, the radar device 300 may be structured to include a single antenna that functions as both the transmitting antenna 130 and the receiving antenna 140, replacing the transmitting antenna 130 and the receiving antenna 140. In this case, for example, the transmitting unit 120 transmits the transmitting signal to the transmitting antenna 130 via a circulator. Furthermore, for example, the receiving unit 150 receives the receiving signal from the receiving antenna 140 via a circulator.

[0050] Display Processing Department

[0051] The display processing unit 202 performs the following processing: based on the echo data of each segmented target region received from the signal processing unit 100, it generates echo data, i.e., composite data, in the target region, and displays the echo image in the target region on a display device (not shown) based on the generated composite data.

[0052] <Signal Processing Department>

[0053] Figure 2 This is a diagram showing the structure of the signal processing unit in a radar device according to an embodiment of the present invention. (Refer to...) Figure 2 The signal processing unit 100 includes an interference removal unit 20, a window function / Fast Fourier Transform (FFT) processing unit 30, and an absolute value / logarithmic conversion unit 40.

[0054] The interference removal unit 20 performs FFT preprocessing as described below: during each sweep period T, it receives N beat signals SD from the A / D conversion unit 170 and removes the interference component (based on the interference wave) from the components of the received beat signals SD. For example, if the interference removal unit 20 detects a beat signal SD(n) containing an interference wave during the FFT preprocessing, it replaces the amplitudes of the I signal Si(n) and the Q signal Sq(n) in the beat signal SD(n) containing the interference wave with zero, thereby removing the interference component. The interference removal unit 20 outputs the FFT-preprocessed beat signal SD(n) to the window function / FFT processing unit 30.

[0055] During each sweep period T, the window function / FFT processing unit 30 performs window function processing by multiplying the N beat signals SD(n) received from the interference removal unit 20 after FFT preprocessing by a predetermined window function, and performs FFT processing and other processing on the beat signals SD(n) after window function processing, thereby generating composite data DI. The window function / FFT processing unit 30 outputs the generated composite data DI to the absolute value / logarithmic conversion unit 40. Details of the window function processing and FFT processing performed by the window function / FFT processing unit 30 will be described later.

[0056] The absolute value / logarithmic conversion unit 40 performs a logarithmic conversion on the absolute value of the composite data DI received from the window function / FFT processing unit 30 to generate echo data, and outputs the generated echo data to the display processing unit 202.

[0057] <Window Function / FFT Processing Unit>

[0058] Figure 3 This is a diagram illustrating the structure of the window function / FFT processing unit in the signal processing unit according to an embodiment of the present invention. (Refer to...) Figure 3 The window function / FFT processing unit 30 includes an extraction signal generation unit 31, a conversion unit 32, and a synthesis data generation unit 33. The extraction signal generation unit 31 includes window function processing units 31A, 31B, and 31C. The conversion unit 32 includes FFT processing units 32A, 32B, and 32C.

[0059] (Signal generation unit)

[0060] The extraction signal generation unit 31 generates multiple extraction beat signals E, which are extracted from a processed signal generated based on beat signals, based on multiple different time ranges. For example, the extraction signal generation unit 31 generates multiple extraction beat signals E based on beat signals SD(n) of different time ranges within the target time region Ta, based on the beat signals SD(n) of the target time region Ta. The beat signals SD(n) of the target time region Ta are an example of the processed signal.

[0061] More specifically, window function processing units 31A, 31B, and 31C each receive beat signals SD(n) from the interference removal unit 20, and generate an extracted beat signal E based on the beat signals SD(n) of a predetermined target time region Ta, which are part or all of the received beat signals SD(n). For example, each of the window function processing units 31A, 31B, and 31C generates an extracted beat signal E comprising an extracted I signal Ei and an extracted Q signal Eq, based on all of the N beat signals SD(n) received from the interference removal unit 20, i.e., the beat signals SD(n) of the target time region Ta.

[0062] Here, the following situation exists: the window function processing unit 31A, window function processing unit 31B, and window function processing unit 31C receive, for example, a beat signal SD(n) whose amplitude of a portion of the I signal Si(n) and the Q signal Sq(n) is replaced with zero from the interference removal unit 20, as the beat signal SD(n) with the interference component removed.

[0063] Figure 4 as well as Figure 5 This diagram illustrates an example of a beat signal received from the interference removal unit by the window function / FFT processing unit in the signal processing unit of an embodiment of the present invention. Figure 5 yes Figure 4 A magnified view of region R1 in the image. Figure 4 as well as Figure 5 In the diagram, the horizontal axis represents the sampling number n of the beat signal SD(n), and the vertical axis represents the amplitude. Figure 4 as well as Figure 5 The solid line in the diagram represents the I signal Si(n) in the beat signal SD(n). Figure 4 as well as Figure 5 The dashed line in the diagram represents the Q signal Sq(n) in the beat signal SD(n).

[0064] Reference Figure 4 as well as Figure 5For example, window function processing units 31A, 31B, and 31C receive from the interference removal unit 20 the beat signal SD(n) whose amplitude is replaced with zero, and the I signal Si(n) and Q signal Sq(n) with sampling numbers n of 170 to 175.

[0065] For example, window function processing units 31A, 31B, and 31C perform window function processing on the beat signals SD(n) received from the interference removal unit 20. Each of the window function processing units 31A, 31B, and 31C multiplies the beat signals SD(n) by multiple window functions Wf with different passing time regions, thereby generating multiple extracted beat signals E. That is, in the window function processing, each of the window function processing units 31A, 31B, and 31C multiplies the N beat signals SD(n) received from the interference removal unit 20 by window functions Wf, which have different passband time regions (i.e., passing time regions TP), thereby generating extracted beat signals E.

[0066] More specifically, the window function processing unit 31A multiplies the I signal Si(n) and Q signal Sq(n) in the beat signal SD(n) by the window function WfA (also known as the third window function) to generate the extracted beat signal E, i.e., the extracted beat signal EA, which includes the extracted I signal EiA and the extracted Q signal EqA.

[0067] Furthermore, the window function processing unit 31B multiplies the I signal Si(n) and Q signal Sq(n) in the beat signal SD(n) by the window function WfB (also known as the first window function), thereby generating the extracted beat signal E, i.e., the extracted beat signal EB, which includes the extracted I signal EiB and the extracted Q signal EqB.

[0068] Furthermore, the window function processing unit 31C multiplies the I signal Si(n) and Q signal Sq(n) in the beat signal SD(n) by the window function WfC (also known as the second window function), thereby generating the extracted beat signal E, i.e., the extracted beat signal EC, which includes the extracted I signal EiC and the extracted Q signal EqC.

[0069] Figure 6 This diagram illustrates an example of a window function used in the signal processing unit / FFT processing unit of an embodiment of the present invention. Figure 6 In the diagram, the horizontal axis represents the sampling number n of the beat signal SD(n), and the vertical axis represents the window weight of the window function Wf. As mentioned above, the sampling number n corresponds to the elapsed time counted from the start of the sweep period T. Figure 6 The solid line in the figure represents the window function WfA used in the window function processing performed by the window function processing unit 31A. Figure 6The dashed line in the figure represents the window function WfB used in the window function processing performed by the window function processing unit 31B. Figure 6 The single-dotted line in the figure represents the window function WfC used in the window function processing performed by the window function processing unit 31C.

[0070] Reference Figure 6 The time span of window function WfA, i.e., the time span TPA, is from time t0 corresponding to sample number n = zero to time tN corresponding to sample number n = N. Similarly, the time span of window function WfB, i.e., the time span TPB, is from time t0 corresponding to sample number n = zero to time tk corresponding to sample number n = k. Furthermore, the time span of window function WfC, i.e., the time span TPC, is from time t(k+1) corresponding to sample number n = (k+1) to time tN corresponding to sample number n = N. Here, k is an integer greater than or equal to 2 and less than N, for example, the integer closest to N / 2. That is, the time spans TPA, TPB, and TPC correspond to the entire time span of the object time span Ta, the first half of the object time span Ta, and the second half of the object time span Ta, respectively. For example, multiple window functions Wf may contain designs with the same shape. Figure 6 In the example shown, the window functions WfB and WfC have the same shape across time regions TPB and TPC. Furthermore, the shapes of the window functions WfA, WfB, and WfC are not limited to [specific shapes]. Figure 6 The shape shown can also be other shapes.

[0071] For example, the extraction signal generation unit 31 generates multiple extraction beat signals E based on temporally continuous time ranges. That is, the extraction signal generation unit 31 generates multiple extraction beat signals E based on beat signals SD(n) that are temporally continuous. More specifically, the time from time t0 to time tk (i.e., the time region TPB) and the time from time t(k+1) to time tN (i.e., the time region TPC) are temporally sequentially continuous time regions. The window function processing units 31B and 31C multiply the beat signal SD(n) by window functions WfB and WfC, respectively, thereby generating extraction beat signals EB and EC based on beat signals SD(n) that are temporally continuous.

[0072] For example, the extraction signal generation unit 31 generates an extraction beat signal E based on a time range containing multiple time ranges, as one of the extraction beat signals E. That is, the extraction signal generation unit 31 generates an extraction beat signal E based on the beat signal SD(n) of the target time region Ta, as one of multiple extraction beat signals E. More specifically, the time region TPA is the time region corresponding to the target time region Ta. The window function processing unit 31A multiplies the beat signal SD(n) by the window function WfA, thereby generating an extraction beat signal EA based on the beat signal SD(n) of the target time region Ta.

[0073] For example, time regions TPA and TPB include sampling numbers n corresponding to times 170-175, while time region TPC does not include sampling numbers n corresponding to times 170-175. That is, the extracted beat signals EA and EB include I signal Si(n) and Q signal Sq(n) with amplitudes replaced by zero, while the extracted beat signal EC does not include I signal Si(n) and Q signal Sq(n) with amplitudes replaced by zero.

[0074] Window function processing units 31A, 31B, and 31C respectively output the generated extraction beat signal EA, extraction beat signal EB, and extraction beat signal EC to FFT processing units 32A, 32B, and 32C in the conversion unit 32.

[0075] (Transition Section)

[0076] The conversion unit 32 converts multiple extracted beat signals E into amplitude data DS representing the relationship between distance and amplitude. That is, the conversion unit 32 converts the multiple extracted beat signals E, which are complex signals, into amplitude data DS representing the relationship between distance d and amplitude, starting from the radar device 300.

[0077] More specifically, the conversion unit 32 receives multiple extracted beat signals E from the extracted signal generation unit 31, performs FFT processing on the received extracted beat signals E, thereby generating a power spectrum P as a complex signal. Furthermore, the conversion unit 32 performs processing such as multiplying the frequencies in each power spectrum P generated corresponding to each extracted beat signal E by a coefficient C to convert the frequencies into distance d, thereby generating amplitude data DS as a complex signal corresponding to each extracted beat signal E.

[0078] Specifically, the FFT processing unit 32A receives the extracted beat signal EA from the window function processing unit 31A and performs FFT processing on the received extracted beat signal EA to generate a power spectrum PA. Furthermore, the FFT processing unit 32A performs a process of multiplying the frequencies in the generated power spectrum PA by a coefficient C to convert the frequencies into distance d, thereby generating amplitude data DSA representing the relationship between distance d and amplitude.

[0079] Furthermore, the FFT processing unit 32B receives the extracted beat signal EB from the window function processing unit 31B and performs FFT processing on the received extracted beat signal EB to generate the power spectrum PB. The FFT processing unit 32B then multiplies the frequencies in the generated power spectrum PB by a coefficient C to convert the frequencies to distance d, and doubles both the I and Q data in the power spectrum PB to generate amplitude data DSB representing the relationship between distance d and amplitude. Here, the transit time region TPB of the window function WfB is half the transit time region TPA of the window function WfA, therefore the output of the power spectrum PB is half the power spectrum PA. Therefore, the FFT processing unit 32B doubles both the I and Q data in the power spectrum PB to compensate for the ratio of the power spectrum P caused by the ratio of the transit time region TP of the window function Wf. For example, when the time region TPB of the window function WfB is 1 / K of the time region TPA of the window function WfA, the FFT processing unit 32B performs a process of setting the I data and Q data in the power spectrum PB to a factor of K in order to compensate for the ratio of the output of the power spectrum PB to the power spectrum PA.

[0080] Furthermore, the FFT processing unit 32C receives the extracted beat signal EC from the window function processing unit 31C and performs FFT processing on the received extracted beat signal EC to generate a power spectrum PC. The FFT processing unit 32C then converts the frequencies in the generated power spectrum PC into distance d by multiplying them by a coefficient C. Similar to the FFT processing unit 32B, it also doubles the I and Q data in the power spectrum PC to generate amplitude data DSC representing the relationship between distance d and amplitude.

[0081] Figure 7 This is a diagram illustrating an example of amplitude data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention. Figure 7 In the figure, the horizontal axis represents the distance d [m], and the vertical axis represents the amplitude [dB]. Figure 7 The dashed line in the figure represents the amplitude Xa of the amplitude data DSA. Figure 7 The single-dotted line in the figure represents the amplitude Xb of the amplitude data DSB. Figure 7 The double-dotted line in the figure represents the amplitude Xc of the amplitude data DSC.

[0082] Reference Figure 7 Compared to amplitude data DSA and DSB, amplitude data DSC has a smaller distance sidelobe. This is because, as mentioned above, the extracted beat signals EA and EB include I signal Si(n) and Q signal Sq(n) with amplitudes replaced by zero, while the extracted beat signal EC does not include I signal Si(n) and Q signal Sq(n) with amplitudes replaced by zero.

[0083] FFT processing units 32A, 32B, and 32C respectively output the generated amplitude data DSA, DSB, and DSC to the comprehensive data generation unit 33.

[0084] (Comprehensive Data Generation Department)

[0085] The data generation unit 33 generates composite data that combines multiple amplitude data. More specifically, the data generation unit 33 generates composite data DI that represents the relationship between distance d and amplitude based on the amplitude of each distance d in the amplitude data DSA, amplitude data DSB, and amplitude data DSC.

[0086] For example, the comprehensive data generation unit 33 selects any one of the amplitude data DSA, amplitude data DSB, and amplitude data DSC for each distance d, thereby generating comprehensive data DI. As an example, the comprehensive data generation unit 33 takes the minimum value of the amplitude data DSA, amplitude data DSB, and amplitude data DSC, thereby generating comprehensive data DI as the set of minimum values ​​of the amplitude data DSA, amplitude data DSB, and amplitude data DSC.

[0087] More specifically, the data generation unit 33 calculates: the absolute value of amplitude ampA(d) of each distance d of amplitude data DSA, expressed by the following equation (1); the absolute value of amplitude ampB(d) of each distance d of amplitude data DSB, expressed by the following equation (2); and the absolute value of amplitude ampC(d) of each distance d of amplitude data DSC, expressed by the following equation (3).

[0088] ampA(d)=(Ia)^2+(Qa)^2…(1)

[0089] ampB(d)=(Ib)^2+(Qb)^2…(2)

[0090] ampC(d)=(Ic)^2+(Qc)^2…(3)

[0091] Here, (Ia)^2 + (Qa)^2 is the sum of the squares of the I and Q data in the amplitude data DSA. (Ib)^2 + (Qb)^2 is the sum of the squares of the I and Q data in the amplitude data DSB. (Ic)^2 + (Qc)^2 is the sum of the squares of the I and Q data in the amplitude data DSC.

[0092] Furthermore, the data generation unit 33 selects the minimum value of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d) for each distance d. Hereinafter, the distance d when the minimum value of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d) is the absolute amplitude value ampA(d) is defined as distance da, the distance d when the minimum value of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d) is the absolute amplitude value ampB(d) is defined as distance db, and the distance d when the minimum value of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d) is the absolute amplitude value ampC(d) is defined as distance dc.

[0093] That is, based on the comparison results of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d), the comprehensive data generation unit 33 determines the distance d to be any one of the distances da, db, and dc.

[0094] Furthermore, the comprehensive data generation unit 33 selects the amplitude corresponding to distance da in amplitude data DSA, the amplitude corresponding to distance db in amplitude data DSB, and the amplitude corresponding to distance dc in amplitude data DSC, and generates comprehensive data DI containing the selected amplitudes.

[0095] Figure 8 as well as Figure 9 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention. Figure 9 yes Figure 8 A magnified view of region R2 in the image. Figure 8 as well as Figure 9 In the figure, the horizontal axis represents the distance d [m], and the vertical axis represents the amplitude [dB]. Figure 8 as well as Figure 9 The solid line in the figure represents the amplitude of the composite data DI. Figure 8 as well as Figure 9 The dashed line in the figure represents the amplitude of the amplitude data DSA. Figure 8 as well as Figure 9 The single-dotted line in the figure represents the amplitude of the amplitude data DSB. Figure 8 as well as Figure 9 The double-dotted line in the figure represents the amplitude of the amplitude data DSC.

[0096] Reference Figure 8 as well as Figure 9 The comprehensive data generation unit 33 generates comprehensive data DI, which is a set of minimum values ​​of amplitude of amplitude data DSA, amplitude of amplitude data DSB, and amplitude of amplitude data DSC.

[0097] The integrated data generation unit 33 outputs the generated integrated data DI to the absolute / logarithmic conversion unit 40.

[0098] Figure 10 as well as Figure 11 This is a diagram illustrating an example of the synthesized data generated in the window function / FFT processing unit of the signal processing unit according to an embodiment of the present invention. Figure 10 yes Figure 11 A magnified view of region R3 in the image. Figure 10 as well as Figure 11 In the figure, the horizontal axis represents the distance d [m], and the vertical axis represents the amplitude [dB]. Figure 10 as well as Figure 11 The solid line in the figure represents the amplitude of the composite data DI. Figure 10 as well as Figure 11 The dashed line in the figure represents amplitude data DSA_1, which is generated by performing FFT processing on the extracted beat signal EA based on the beat signal SD(n) with interference and its region being replaced with zero. Figure 10 as well as Figure 11 The single-dot dash in the figure represents amplitude data DSA_2, which is generated by FFT processing of the extracted beat signal EA based on the ideal beat signal SD(n) without interference and without regions that are replaced to zero.

[0099] Reference Figure 10 as well as Figure 11 The amplitude data DSA_1 generated based on the beat signal SD(n) with interference components removed has a larger range sidelobe compared to amplitude data DSA_2. On the other hand, the composite data DI has the same peak shape as amplitude data DSA_1 and amplitude data DSA_2, but has a smaller range sidelobe compared to amplitude data DSA_1. Therefore, in the radar device 100 of the embodiment of the present invention, composite data DI can be generated based on the beat signal SD(n) with interference components removed, which can ensure the same peak shape as the ideal beat signal without interference and has a small range sidelobe. Therefore, the target can be detected more accurately based on the composite data DI.

[0100] [Action Flow]

[0101] The radar device according to an embodiment of the present invention includes a computer containing a memory. The computer's central processing unit (CPU) and other arithmetic processing units read some or all of the following flowchart and sequence steps from the memory and execute them. The program can be installed externally. The program can be stored on a recording medium or transmitted via a communication line.

[0102] Figure 12 This is a flowchart that specifies an example of the operation flow for generating comprehensive data by the radar device according to an embodiment of the present invention.

[0103] Reference Figure 12 First, the radar device 300 multiplies the beat signal SD(n) by window functions WfA, WfB, and WfC respectively to generate the extracted beat signal EA, extracted beat signal EB, and extracted beat signal EC (step S102).

[0104] Next, the radar device 300 performs FFT processing on the extracted beat signal EA, extracted beat signal EB, and extracted beat signal EC, thereby converting the extracted beat signal EA, extracted beat signal EB, and extracted beat signal EC into amplitude data DSA, amplitude data DSB, and amplitude data DSC (step S104).

[0105] Next, the radar device 300 calculates the absolute amplitude value ampA(d) of each distance d of the amplitude data DSA, the absolute amplitude value ampB(d) of each distance d of the amplitude data DSB, and the absolute amplitude value ampC(d) of each distance d of the amplitude data DSC (step S106).

[0106] Next, the radar device 300 selects the minimum value of the absolute amplitude values ​​ampA(d), ampB(d), and ampC(d) for each distance d, and assigns the distance d to any one of the distances da, db, and dc (step S108).

[0107] Next, the radar device 300 generates integrated data DI, which includes the amplitude corresponding to the distance da in the amplitude data DSA, the amplitude corresponding to the distance db in the amplitude data DSB, and the amplitude corresponding to the distance dc in the amplitude data DSC (step S110).

[0108] Furthermore, in the signal processing unit 100 of the embodiment of the present invention, the following structure is adopted: the extracted signal generation unit 31 multiplies the beat signal SD(n) by window functions WfA, WfB, and WfC, which are different time regions of the passband, thereby generating extracted beat signals EA, EB, and EC, but it is not limited to this. Alternatively, the extracted signal generation unit 31 may not use window functions WfA, WfB, and WfC, but instead extracts a portion or all of the beat signal SD(n) to generate extracted beat signals EA, EB, and EC, which are beat signals SD(n) with multiple different time ranges.

[0109] Furthermore, the signal processing unit 100 of the embodiment of the present invention employs a structure in which the signal extraction generation unit 31 generates extracted beat signals EB and EC based on beat signals SD(n) that are sequentially consecutive in time, but is not limited to this. It may also have a structure in which the signal extraction generation unit 31 generates extracted beat signals EB and EC based on beat signals SD(n) that are partially repeated in time. That is, the beat signals can be repeated in time through time regions TPB and TPC. However, by generating extracted beat signals EB and EC based on beat signals SD(n) that are sequentially consecutive in time by the signal extraction generation unit 31, it is possible to prevent the same I signal Si(n) and Q signal Sq(n) whose amplitudes are replaced to zero in the interference removal unit 20 from being included in the extracted beat signals EB and EC.

[0110] Furthermore, the signal processing unit 100 in the embodiment of the present invention employs a structure in which the extraction signal generation unit 31 generates an extraction beat signal EA based on the beat signal SD(n) of the target time region Ta, but is not limited to this. It may also have a structure in which the extraction signal generation unit 31 generates extraction beat signals EB and EC, but does not generate extraction beat signal EA. That is, the extraction signal generation unit 31 may also have a structure that does not include the window function processing unit 31A.

[0111] Furthermore, the signal processing unit 100 of the embodiment of the present invention employs a structure in which the extraction signal generation unit 31 generates extraction beat signals EA, EB, and EC, but is not limited to this. The extraction signal generation unit 31 may also generate two or more extraction beat signals E. For example, it may be structured such that the extraction signal generation unit 31 generates M extraction beat signals E based on beat signals SD(n) that divide the target time region Ta into M distinct time ranges. That is, it may be structured such that the extraction signal generation unit 31 includes M window function processing units, which multiply the beat signals SD(n) by M window functions Wf having distinct passage time regions TP, thereby generating beat signals E respectively. Here, M is an integer of 2 or more. The larger M is, the smaller the distance sidelobe of the composite data DI can be generated, even when the beat signal SD(n) contains more interference waves. On the other hand, the smaller M is, the simpler the structure of the window function / FFT processing unit 30 can be.

[0112] Furthermore, the signal processing unit 100 in the embodiment of the present invention employs a structure in which the comprehensive data generation unit 33 generates comprehensive data DI, which is a set of minimum values ​​of the amplitudes of amplitude data DSA, amplitude data DSB, and amplitude data DSC, but it is not limited to this. Alternatively, the comprehensive data generation unit 33 may generate comprehensive data DI by performing calculations such as averaging the amplitudes of amplitude data DSA, amplitude data DSB, and amplitude data DSC.

[0113] Furthermore, a technology is desired that can more accurately detect targets based on beat signals.

[0114] For example, the radar system described in Patent Document 1 has a structure that includes a signal processing path that removes interfering waves from the beat signal and a signal processing path that does not remove interfering waves from the beat signal. In this structure, the range sidelobes in the power spectrum generated based on the beat signal increase, making it impossible to accurately detect the target.

[0115] In contrast, in the signal processing unit 100 of this embodiment, the extracted signal generation unit 31 generates extracted beat signals EA, EB, and EC. These extracted beat signals EA, EB, and EC are processed signals generated from beat signals based on transmitted and received signals, and are extracted based on multiple different time ranges. The conversion unit 32 converts the extracted beat signals EA, EB, and EC into amplitude data DSA, DSB, and DSC, representing the relationship between distance d and amplitude. The comprehensive data generation unit 33 generates comprehensive data DI, which combines the amplitude data DSA, DSB, and DSC.

[0116] In this way, extracted beat signals EA, EB, and EC are generated from the processed signal based on beat signals, extracted based on multiple time ranges. These extracted beat signals EA, EB, and EC are then converted into amplitude data DSA, DSB, and DSC, respectively. Finally, a composite data DI is generated by combining these multiple amplitude data DSA, DSB, and DSC. With this structure, for example, the composite data DI can be generated using the amplitude data DSC of the extracted beat signal EC, which does not contain a beat signal SD(n) whose amplitude is replaced to zero for interference removal. Therefore, the increase in range sidelobes in the composite data DI caused by the replacement of a portion of the amplitude of the beat signal SD(n) to zero can be suppressed, thereby enabling more accurate target detection based on the composite data DI with smaller range sidelobes. Therefore, more accurate target detection is possible based on the beat signal SD(n).

[0117] Furthermore, in the signal processing unit 100 of the embodiment of the present invention, the extraction signal generation unit 31 generates the extraction beat signal EA, the extraction beat signal EB, and the extraction beat signal EC by multiplying the processed signal by multiple window functions with different time regions.

[0118] With this structure, for example by performing Fourier transforms on the extracted beat signals EA, EB, and EC generated using appropriate window functions, it is possible to generate amplitude data DSA, DSB, and DSC with smaller errors.

[0119] Furthermore, in the signal processing unit 100 of the embodiment of the present invention, the comprehensive data generation unit 33 generates comprehensive data DI by selecting any one of amplitude data DSA, amplitude data DSB, and amplitude data DSC corresponding to each distance d.

[0120] With this structure, for example, it is possible to selectively use amplitude data DS with the smallest distance from the sidelobe to easily generate composite data DI with even smaller distance from the sidelobe.

[0121] Furthermore, in the signal processing unit 100 of the embodiment of the present invention, the extraction signal generation unit 31 generates extraction beat signal EB and extraction beat signal EC based on a time range that is continuous in time.

[0122] With this structure, for example, it is possible to suppress the inclusion of a beat signal SD(n) whose amplitude is replaced to zero in order to remove interference components in both the extracted beat signal EB and the extracted beat signal EC. Therefore, it is possible to suppress the increase in range sidelobes caused by the amplitude of the beat signal SD(n) being replaced to zero in at least one of the amplitude data DSB and amplitude data DSC based on the extracted beat signal EB and the extracted beat signal EC.

[0123] Furthermore, in the signal processing unit 100 of the embodiment of the present invention, the extraction signal generation unit 31 generates an extraction beat signal EA based on a time range including multiple time ranges, as one of the extraction beat signals E.

[0124] With this structure, higher range resolution amplitude data DSA can be generated from the extracted beat signal EA based on the beat signal SD(n) with more samples. Therefore, higher range resolution composite data DI can be generated using amplitude data DSA.

[0125] Furthermore, in the signal processing unit 100 of the embodiments of the present invention, the window functions include those with the same shape design.

[0126] With this structure, it is no longer necessary to perform correction processing for the extracted beat signal corresponding to different window function shapes, and it is possible to generate composite data DI with a simple structure and processing.

[0127] Furthermore, the radar device 300 according to an embodiment of the present invention includes a signal processing unit 100, a transmitting unit 120, and a receiving unit 150. The transmitting unit 120 transmits a transmission signal. The receiving unit 150 receives the reflected signal, i.e., the signal reflected by the target, of the transmitted transmission signal.

[0128] With this structure, a radar device 300 can be realized that can detect targets more accurately based on beat signal SD(n).

[0129] Furthermore, in the radar device 300 of the embodiment of the present invention, the transmitting unit 120 transmits a transmission signal via a rotating transmitting antenna 130, and the receiving unit 150 receives a reflected signal via a rotating receiving antenna 140.

[0130] This structure allows for the transmission of signals in all directions and the reception of reflected signals, thus enabling the detection of targets over a wider range.

[0131] Furthermore, the radar signal processing method of the present invention is used in the signal processing unit 100 of the radar device 300. In this radar signal processing method, firstly, the signal processing unit 100 generates extracted beat signals EA, EB, and EC, which are extracted from a processed signal generated based on beat signals of transmitted and received signals, based on multiple different time ranges. Next, the signal processing unit 100 converts the extracted beat signals EA, EB, and EC into amplitude data representing the relationship between distance d and amplitude. Next, the signal processing unit 100 generates composite data DI, which is a combination of amplitude data DSA, amplitude data DSB, and amplitude data DSC.

[0132] In this way, extracted beat signals EA, EB, and EC are generated from the processed signal based on the beat signal and derived from multiple time ranges. These extracted beat signals EA, EB, and EC are then converted into amplitude data DSA, DSB, and DSC, respectively. Finally, a composite data DI is generated by combining these multiple amplitude data DSA, DSB, and DSC. Using this method, for example, the composite data DI can be generated using the amplitude data DSC of the extracted beat signal EC, which does not contain a beat signal SD(n) whose amplitude is replaced to zero for interference removal. Therefore, the increase in range sidelobes in the composite data DI caused by the replacement of a portion of the amplitude of the beat signal SD(n) to zero can be suppressed, thus enabling more accurate target detection based on the composite data DI with smaller range sidelobes. Therefore, more accurate target detection is possible based on the beat signal SD(n).

[0133] It should be considered that the embodiments described are illustrative and not restrictive in all respects. The scope of the invention is shown by the claims rather than the description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A radar signal processing device, comprising: The signal generation unit is configured as follows: Processing signals are generated based on the beat signals of the transmitted and received signals, and Multiple extraction beat signals are generated by applying multiple window functions to the processed signal, wherein the first and second window functions of the multiple window functions do not overlap in time, and the third window function of the multiple window functions overlaps in time with both the first and second window functions; A conversion unit configured to convert the plurality of extracted beat signals into amplitude data representing the relationship between distance and amplitude; as well as A comprehensive data generation unit is configured to integrate multiple amplitude data into comprehensive data.

2. The radar signal processing apparatus according to claim 1, wherein... The integrated data generation unit is further configured to select the amplitude of one of the multiple amplitude data into the integrated data corresponding to each of the distances.

3. The radar signal processing apparatus according to claim 1 or 2, wherein... The multiple window functions have the same type.

4. A radar device, comprising: The radar signal processing apparatus according to any one of claims 1 to 3; A transmitting unit configured to transmit the transmitted signal; as well as A receiving unit configured to receive the reflected signal reflected by the target.

5. The radar device according to claim 4, wherein... The transmitting unit is configured to transmit the signal via a rotating antenna. The receiving unit is configured to receive the reflected signal via a rotating antenna.

6. A radar signal processing method, comprising: The processing signal is generated based on the beat signal between the transmitted and received signals; Multiple extraction beat signals are generated by applying multiple window functions to the processed signal, wherein the first and second window functions of the multiple window functions do not overlap in time, and the third window function of the multiple window functions overlaps in time with both the first and second window functions; The multiple extracted beat signals are converted into amplitude data representing the relationship between distance and amplitude; as well as The multiple amplitude data are combined into a composite data.

7. A storage medium having stored thereon computer-executable instructions, which, when executed by a computer, cause the computer to: The processing signal is generated based on the beat signal between the transmitted and received signals; Multiple extraction beat signals are generated by applying multiple window functions to the processed signal, wherein the first and second window functions of the multiple window functions do not overlap in time, and the third window function of the multiple window functions overlaps in time with both the first and second window functions; The multiple extracted beat signals are converted into amplitude data representing the relationship between distance and amplitude; as well as The multiple amplitude data are combined into a composite data.

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